The New Hampshire Department of Agriculture said it found larvae of the emerald ash borer beetle in a tree in Concord.

The beetle has been moving eastward for years, most recently turning up in Massachusetts and Connecticut.

The state has been preparing for the arrival of this beetle for some time now, but now that it's here -- little if anything can be done to stop it.

The clock is running out on New Hampshire's ash trees.

"The Emerald Ash Borer is probably the most destructive forest insect that we have in the country, on the continent currently. It's an invasive species from Asia, and it's been spreading from state to state," said Lorraine Merrill, commissioner of N.H. Dept. Of Agriculture.

The beetle can destroy an ash tree in 3 to 5 years and has already killed millions of trees in the midwest. The state will be surveying trees in Concord to determine the scope of the infestation.

"We have a plan that we are beginning to implement, and there will be information coming out for homeowners and municipalities," said Merrill.

Ash trees make up about 6 percent of the state's forests, but with the beetle setting up camp, experts said that figure will begin to drop.

"From the parts of the country and Canada it has affected so far, it devastates the Ash population very quickly," said Rob Farquhar, general manager of Brochu Nurseries.

Farquhar said the beetle tends to stay in the canopy of the ash tree, making it hard to spot.

"I doubt the regular homeowner is going to be cognizant of it until it's too late," said Farquhar.

Anticipating the beetle's advance, Brochu began phasing out ash production four years ago. More established specimens, like the majestic ash tree on the statehouse lawn, won't be so lucky. Deputy Secretary of State David Scanlan is a forester and said the emerald borer is bad news for New Hampshire.

"Each tree species that grows in our forests is an important component of our forests. They all serve a purpose, and to lose one of them really has a big impact," said Scanlan.

The presence of this beetle triggers a federal quarantine on certain ash wood products, but the commissioner of agriculture said its too soon to determine what the scope of that quarantine will be.